Pipeline system



May 15, 1962 R. A. WATKINS 3,034,525

PIPELINE SYSTEM Filed June 24, 1960 INVENTOR ROBERT A. WATKINS AT ORNEY United States Patent ()fifice 3,034,525 Patented May 15, 1962 3,034,525 PIPELINE SYSTEM Robert A. Watkins, Beaumont, Tex., assignor to E. I. (in Pont de Nemours and Company, Wilmington, DeL, a corporation of Delaware Filed June 24, 1960, Ser. No. 38,513 Claims. (Cl. 137-1) The present invention relates to a technique for the safe transport of molten trinitrotoluene (TNT). More particularly, the present invention relates to a procedure whereby molten TNT may be safely pumped through a pipeline from one place to another.

This case is a continuation-in-part of my prior copending application Serial No. 670,639, filed July 9, 1957, now abandoned.

In the manufacture of explosives and blasting agents which contain TNT, it is often necessary to pump or transport TNT in the molten state. This requires a suitable pipeline network for conveying the TNT from one point to another. There is an inherent danger under such circumstances that an accidental detonation in any one location will propagate along the TNT-containing pipelines and initiate explosive materials at distant locations thereby gravely endangering many personnel who would not otherwise be exposed to the initial blast. It is thus extremely important from a safety standpoint that any accidental explosion be confined to its place of origin and not be permitted to propagate through connecting pipelines to other areas having substantial quantities of explosive compositions.

It is an object of the present invention to provide a method and means for the safe transport of molten TNT. It is a further object of the present invention to provide a procedure whereby molten TNT may be safely pumped from one place to another using, for the most part, conventional piping. It is a still further object of the present invention to prevent an accidental detonation from propagating beyond its place of origin. Other and additional objects will become apparent from a consideration of the ensuing specification and claims.

Broadly speaking, the invention involves the use of interrupter sections of plastic pipe interposed at appropriate places in conventional metal piping. I have found that the presence of a section of plastic pipe in the pipeline will halt the progress of a detonation of the TNT which is progressing along the pipe. By plastic pipe I mean piping formed of any common organic plastic composition, such as polyethylene, polyvinylchloride, polytetrafiuoroethylene, or any of these reinforced with steel mesh or a metal pipe coated with plastic throughout its interior surface, as will be more particularly hereinafter described.

Reference is made to the attached drawing which is a cross-sectional View of a pipeline for molten TNT that has been provided with an interrupter section in accordance with the present invention.

In the drawing, 1a and 1b represent lengths of conventional steel piping connected by a section 2 of plastic pipe, e.g. polyvinylchloride or polytetrafluoroethylene. The plastic pipe 2 is securely coupled at either end to the steel pipes 1a and 11b, for example, by means of tight wire wraps 3a and 3b. The entire line is filled with flowing molten TNT 4. In lieu of the plain plastic pipe 2 a wire mesh reinforced plastic pipe may be used or a steel pipe having an interior plastic coating.

The invention is illustrated by the following examples.

Example 1 V This example illustrates the general technique employed. TNT was reduced to the molten state by heating to a temperature above about 180 F. The molten TNT was poured into pipe sections of various compositions and dimensions. A small reservoir containing molten TNT was aflixed to one end of each of the pipe sections to be tested. The TNT was initiated in each case by about 65 grams of RDX primed with a No. 6 electric blasting cap. In each instance, the initiating charge was submerged in the molten TNT contained in the small reservoir. The extent of propagation in each case was ascertained visually, that is, by observing the length of pipe destroyed.

Example 2 Following the procedure described in Example 1, a four ft. length of schedule 40 steel pipe having an inner diameter (I.D.) of 1.049 inches and an outer diameter (O.D.) of 1.305 inches was loaded with two pounds of molten TNT. When the TNT was initiated, the propagation traveled the complete length of the pipe.

Example 3 Following the procedure described in Example 1, a sixteen ft. length of soft copper tubing having a 1.00 inch ID. and a 1.125 inch O.D. was loaded with 9 pounds of molten TNT. Upon initiation of the TNT, the propagation traveled the complete length of the pipe.

Example 4 Following the procedure described in Example 1, a twenty-two ft. length of Tygon brand polyvinylchloride plastic tube having a one inch ID. and one-quarter inch wall thickness was loaded with eleven pounds of molten TNT. Upon initiation of the TNT, the propagation traveled eight inches along the tubing and then stopped.

Example 5 Following the procedure described in Example 1, a two ft. length of Alathon brand polyethylene plastic tubing having a inch 1.1). and a inch wall thickness was loaded with one pound of molten TNT. Upon initiation of the TNT, the propagation traveled for two inches along the tubing and then stopped.

Example 6 Following the procedure described in Example 1, a four ft. length of copper tubing having a inch ID. and having an 8 inch section in the center thereof replaced by an 8 inch length of Teflon brand polytetrafluoroethylene plastic tubing with a inch ID. and a inch wall thickness was loaded with two pounds of molten TNT. The Teflon section was located 19 inches from the end of the copper tubing at which the reservoir was located. Upon initiation of the TNT, the propagation traveled the 19 inches through the copper tubing and stopped at this point which was the beginning of the section of Teflon tubing.

Example 7 Following the procedure of Example 1, a 6 ft. length of one inch -I.D. copper tubing having a 26 inch section in the center replaced by a 26 inch length of polytetrafluoroethylene tubing with -a inch ID. and a ,5 inch wall thickness was loaded with 6 pounds of molten TNT. The polytetrafiuoroethylene tubing was armored by a woven mesh of steel braid. The plastic section was located 28 inches from the end of the copper tubing at which the reservoir was located. Upon initiation of the TNT, the propagation traveled through the 28 inches of copper tubing and 4 inches into the armored plastic section and stopped at this point.

Example 8 Following the procedure described in Example 1, a 26 inch length of polytetrafluoroethylene plastic pipe armored by a woven mesh of steel braid and having a 78 inch ID. was filled with molten TNT. Upon initiation of the TNT, the propagation traveled 6 inches along the pipe and stopped at this point.

V out.

Example 9 Following the procedure of Example 1, a two ft. length of polyethylene pipe having a inch ID. and a A inch wall thickness was loaded with one pound of molten TNT. The TNT in the pipe as well as the TNT in the reservoir surrounding the initiating charge was permitted to solidify. Upon initiation of the TNT, the propagation traveled 2 inches along the pipe and stopped at this point. This example illustrates the utility of the invention even if the molten TNT in a portion of the pipeline should solidify.

Example Following the procedure of Example 1, a two ft. length of 1 inch LD. steel pipe is coupled to a one foot length of 1% inch 1.13. steel pipe having a uniform interior coating of polyethylene which is /s of an inch thick. A second two ft. length of the 1 inch steel pipe is coupled to the remaining end of the polyethylene lined steel pipe. The inner diameter of the assembled sections is one inch through- The one inch -I.D. steel pipe has a wall thickness of 1.32 inches and the 1% inch I.D. steel pipe has a wall thickness of 1.66 inches. Upon initiation of the TNT, the propagation travels through the one inch steel pipe and about 7 /2 inches into the polyethylene lined steel pipe .and stops at this point.

According to the present invention, the propagation of a detonation in a metal pipeline containing molten TNT will be interrupted and halted if the pipeline contains at some intermediate point a section of pipe formed of an organic plastic material. Best results are achieved from a safety standpoint if the plastic pipe has an inner diameter whichis not greater than about three inches. A two ft. length of plastic pipe interposed in a conventional metal pipeline will normally -halt the propagation of a detonation through the section. However in many cases it will not be necessary to use a section which is two ft. in length. Generally speaking, the length of the section of plastic pipe should be at least about six times the inner diameter of the pipe. Thus, a pipe having a one inch inner diameter need only be about six inchesrin length; a two inch inner diameter pipe about twelve inches in length, etc. The wall thickness of the pipe is preferably no greater than about A of the inner diameter of the pipe.

The organic plastic from which the interrupter section is formed can be any common plastic material which is used for the fabrication of plastic piping such as polyas by clamping or the like. This is conventional in the piping arts and the specific way in which the interrupter section is secured in the pipeline forms no part of the present invention.

1 am not able to explain with certainty the manner in which the plastic interrupter section-halts the propagation of the detonation in the TNT. It is not merely a function of lack of confinement since steel pipe having an interior plastic lining is operable. Contact of the traveling detonation wave with the plastic surface, as distinguished from a metallic surface, somehow afiects the detonation to prevent its further progress. Regardless of the theory of operation, however, the plastic interrupter sections will halt the detonation, as described above. It is thus possible to confine an accidental detonation to the area of origin such that personnel in adjacent areas will not be endangered.

Having this described the invention, I intend to be limited only by the following claims.

1. In a pipeline for the safe conveyance of molten TNT, a section of metallic piping, an interrupter section connected to said piping for the purpose of halting the propagation of detonation, and a second section of metallic piping connected to the end of the interrupter section remote from the first section of metallic piping, said interrupter section comprising a length of organic plastic pipe having an overall length at least about six times as great as its inner diameter and greater than the length of propagation of molten TNT through said interrupter section, said inner diameter being not greater than about three inches.

2. A pipeline as in claim 1 in which said plastic pipe is polyeterafluoroethylene.

3. A pipeline as in claim 1 in which said plastic pipe is polyethylene.

4. A process for the safe transport of molten TNT from one location to another which includes the essential step of pumping said molten TNT through a metallic pipe- 7 line containing an interruptersection of plastic pipe, said ends to the metal piping by my convenient means, such plastic pipe having an inner diameter of not more than about three inches and a length at least about six times as great as the inner diameter-and greater than the length of propagation of molten TNT through said interrupter section.

5. A process as in claim 4 in which the plastic pipe is polyeterafluoroethylene. 7

References Cited in the file of this patent 

